The present invention relates to improvements in methods and apparatus for copying selected or successive sections of a series of sections on a length of photographic material, especially for reproducing the images of successive or selected film frames which form a web or strip of coherent exposed and developed film frames separated by frame lines.
It is already known to copy successive or selected frames of a series of coherent customer films on a web of photographic paper or the like in such a way that the characteristics of copying light are influenced by a number of parameters, particularly by the parameters of individual film frames as well as by one or more parameters of the entire customer film. Reference may be had to commonly owned U.S. Pat. No. 4,279,502 granted July 21, 1981 to Siegfried Thurm et al. which discloses a method and an apparatus for copying successive film frames of a series of customer films which are spliced together to form an elongated web. The web is transported longitudinally from a supply reel to a takeup reel, and successive frames are monitored in a first portion of the elongated path between the two reels in order to gather information pertaining to the parameters of individual frames, and such information is thereupon used to influence the copying operation in a second portion of the same path between the first portion and the takeup reel. The means for monitoring the film frames in the first portion of the path is associated with means for monitoring one or more parameters of an entire customer film, and the thus obtained information is also utilized to influence the copying of the respective film frames. Therefore, the distance between the first and second portions of the path must exceed the length of the longest customer film in the web in order to ensure that the parameter or parameters of the entire customer film will be monitored and the thus gathered information will be available first for evaluation and thereupon for regulation of the copying operation before the foremost frame of the freshly monitored customer film reaches the copying station. A magazine can be provided for temporary storage of a progressively increasing length of a customer film between the monitoring and copying stations while such film is being monitored for the generation and storage of signals which are indicative of the characteristics (e.g., density) of successive frames as well as of the characteristics of the entire customer film. This renders it possible to reduce the distance between the monitoring and the copying stations. A microprocessor is preferably utilized to evaluate the stored signals and to transmit appropriate signals to the copying unit when the respective frames of the customer film which was temporarily stored between the two stations reach the copying station. The microprocessor can ascertain the presence or absence of color dominants in any one of the three primary colors and can influence the exposure of successive film frames to light in the three colors in dependency on the characteristics of signals which are indicative of the parameters of a film frame as well as in dependency on the characteristics of signals which are indicative of one or more parameters of the entire customer film.
An advantage of the just discussed method is that it renders it possible to process a large number of film frames and customer films per unit of time because the monitoring operation takes place simultaneously with the copying operation. However, the practice of such method also necessitates the utilization of highly complex and expensive copying machines which can reproduce the images of successive acceptable film frames at a rate at least approaching the output of the mcnitoring device. Moreover, the utilization of a high-speed and highly complex copying machine is not always desirable and/or necessary, especially if the copies of film frames are to be developed simultaneously with copying. The developing machines cannot keep pace with modern copying machines.